1. Field of the Invention
This invention relates to a catalyst for cracking heavy hydrocarbons to make a light oil, i.e., light gas and cracked oil, and also for producing hydrogen by the reaction between the catalyst and steam utilizing an oxidation-reduction reaction.
2. Description of the Prior Art
As a catalyst for cracking heavy hydrocarbons such as atmospheric residual oil, vacuum residual oil, solvent-deasphalting residue, etc., it has been heretofore proposed to use nickel-containing ore calcined at 900.degree. to 1,200.degree. C. (see Japanese Patent Application (OPI) No. 72388/77 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application") and U.S. Pat. No. 4,115,324).
Also, the inventors of the present invention previously invented a process which comprises catalytically cracking a heavy oil (e.g., atmospheric residual oil, vacuum residual oil, etc.) in the presence of a nickel ore, by which heavy metals contained in the heavy oil are removed and the heavy oil is cracked. See Japanese Patent Application (OPI) No. 10202/74.
As a result of further investigations, the inventors have found that if the above-described heavy hydrocarbon is subjected to catalytic cracking in the presence of laterite or a laterite-containing catalyst, coke is formed on the laterite catalyst in a greater amount as the heavy hydrocarbon is cracked to a light oil, although the yield of cracked distillate oil is slightly decreased when compared to the use of the above-described nickel ore. When the laterite catalyst on which the coke is deposited is heated in a gas stream, the iron oxides in the laterite catalyst are very rapidly reduced and hydrogen is easily formed by the steam-iron reaction. Thus, the inventors proposed a process for producing a cracked distillate and hydrogen from a heavy oil which comprises cracking the heavy oil in the presence of laterite or a laterite-containing catalyst while simultaneously depositing coke on the laterite or laterite-containing catalyst, reducing the laterite or laterite-containing catalysts on which the coke is deposited while simultaneously burning the coke in a reducing atmosphere, and forming a hydrogen-rich gas by contacting the reduced laterite or laterite-containing catalyst with steam. See Japanese Patent Application (OPI) No. 47708/79, Japanese Patent Application No. 9413/79 and U.S. Pat. Ser. No. 22,385, filed Mar. 21, 1979.